Porphyrins and the iron requirement for chlorophyll formation in Euglena.

Abstract

The authors tested the hypothesis that the requirement of Fe in chlorophyll synthesis is due to a requirement for Fe in the conversion of coproporphyrinogen (COPROgen) to protoporphyrin (PROTO). The rate of synthesis of chlorophyll in Euglena gracilis z strain can be made linearly dependent on the Fe content of the cells. Over that part of the range of Fe contents where growth is not limited, the activities of several enzyme systems presumably required for porphyrin formation are also independent of Fe. These include [zeta], -aminolevulinate dehydratase, por-phobilinogen deaminase, and the enzymatic synthesis of COPRO and PROTO from porphobilinogen. The authors concluded that the COPROgen hypothesis seemed not to be correct.